VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1929 Connecting Rod bearings

Hello. I dropped my oil pan and could see bits of metal below the #6 piston in the pan.I looked at the rod cap on #6 and could see fragmented edges at the bearing ends.Could also move the cap end "to and fro" alot compared to the other rod caps.I know this is not right.I had read about babbits and shims.But still not clear about what to do.

Remove the two nuts that hold the cap to the rod. Remove the rod cap. You can push the rod and piston up into the cylinder to see the top half (in he rod)You will than see how the babbit material (bearing material) that is applied to the rod and cap looks. Should look gray like lead and smooth. Sounds as if your got hot and melted. Will than be scored and possibly all melted out and steel exposed.

Last winter I got my 30 in the shop to get it ready for the spring southern tour. While changing oil I thought lets drop the pan and have a look, found babbit chunks in the pan. All the thrust on one side and most of the other side was gone on #1 rod. The crank was fine so I found a NOS rod and replaced #1 and checked all the others, they were fine. That my be a common problem with the old babbit.

The rod did not look over heated, just was flaking off.

That can happen from being stored for years with dirty acid filled oil in the pan. Also can depend as to who rebabbited the rod at one time.

For a 1929 only if it still has the original rods there will be no X groves in the babbit for oil flow.

And, if you replace the rod instead of getting it repoured, it is a good idea to find a rod that is close in weight to the other rods that are in your engine block.

ok so I took the rod cap off and bearing surfaces looked smooth.The sides of the cap have been "dinged up"or smashed because the bearing was very loose causing it to knock to either side.Their were 3 shims on each side.I took one off one at a time to find my proper tightness.The only time I can get the rod not to move side to side with hand pressure is NO shims.Do I just torque it down to 35 ft-lbs and leave it ?Or should I get that plastiguage to see what I have for gap.Could it be Too tight?

It wasn't making noise going from side to side.(unless the coneecting rod is bent) If you took out that many shims and can still move it from side to side by hand it was just plain loose.
You did inspect the upper part of the bearing also?
Its too tight when you cannot move it back and forth by tapping it light;y with a small 8 ounce hammer.
If it were mine I would file the rod cap a bit to tighten it more and add shims if it got too tight. Not everyone may agree with me but was a common cure years ago. I assume you don't normally drive across the country with the car.

I agree with you Gene. The objective is to have a functional vehicle not a race car. I only know a few people that push their old Chevys hard enough that a short cut or two might be a problem.

Thanks guys Ill try that.I did inspect the top bushing and did notice a little spot near the edge where it flaked off from the dinging back and forth.But didnt look like it was spreading.I think it will work for now and leave it.Another question:How the dipper is oriented on the cap in reference to the oil port.5 out 6 have it where the port is near the edge of the dipper as opposed to the Middle of the dipper.Could this greatly affect the oiling process ????Number 1 has it in the middle.

The oil port is near the edge (back edge) of the dipper. #1 either has the rod cap on backwards or the rod is connected to the piston backwards. Look up inside the piston. the clamp bolt that clamps the rod to the wrist pin should be to the camshaft side. If the rod is correct I think it would be best to put the cap on as it should be. This will require adjusting the rod again.
Yes, being the way it is would reduce the amount of oil getting at the rod bearing.

Yep,the cap was put on backwards! Checking the other rod caps for looseness AND TIGHTNESS? Can a rod cap bearing BECOME too tight? Some I cannot move with a tap of a 8 oz hammer.

If correctly adjusted originally they can not become too tight under normal conditions.
Is there some type of coating or deposit on the surfaces? If anti-freeze gets into the oil it can cause things to sieze up. I would remove one of the "tight" caps and see whats up.

Good morning 1929 chevy,

Maybe I can help you with some pictures.
Last year when I bought my 1931 I could find out nobody since decades did clean the oil pan and after hearing some unnormal knocking sounds under conditions of strong hill-up driving I thought now I must take the pan off at once to see what's going on there.
I found a missing dipper at cyl.#1, or better: I found it after scratching out the dirt (like bad mixed cement) of the oil pan. I found it in the dirt.

But I had luck, with my experience the con.rod bearing did look ok, the bearing cap too, I did repair the missing and broken dipper and did fix all together again and had never again problems with unnormal sound or anything like that.

Maybe the pictures at:

http://de.fotoalbum.eu/stefha/a341250

may help you to see how it should look.

All the best
Stefan from germany